What is Turner syndrome?
Turner syndrome is a rare disorder that affects females. Most girls are very short for their age and don't experience normal growth spurts. If untreated, women with Turner syndrome will be very short as adults. Girls and women may also have a square-shaped chest with nipples that are farther apart than usual. Most girls experience premature ovarian failure. The ovaries, which are the two tiny glands that produce eggs and make certain hormones, do not function properly or are absent. This affects a girl's sexual development and ability to have children. Most girls will not go through puberty unless they are treated with female hormones. Even with treatment, most girls are infertile. Some girls and women may have problems with the heart and blood vessels that can cause serious complications. Intelligence is usually not affected, but some girls or women may have trouble with certain mental skills like math or nonverbal memory or spatial relationships. Turner syndrome can be associated with many other problems including hearing loss, eye abnormalities, kidney issues, liver issues, and thyroid disease. There is no cure for Turner syndrome, but there are treatments for many of the problems that develop. The disorder can affect girls very differently. Some girls will have a mild form and may go undiagnosed well into adulthood, while other girls have very severe symptoms in infancy or childhood that affect their quality of life.
Turner syndrome is a chromosomal disorder. Chromosomes are found in the nucleus of every cell. Chromosomes carry the genetic material of a person in the form of genes. Most people have 46 chromosomes; 23 inherited from their mother and 23 from their father. Twenty-two chromosomes are the same in girls and boys, but girls have two X chromosomes and boys have one X and one Y chromosome. These are called the sex chromosomes because they determine the sex of a person. In most instances, Turner syndrome is not inherited and the disorder occurs when all or some of one of the X chromosomes in a girl is missing. When all of a chromosome is missing, it is called a deletion. When all of a chromosome is missing, it is called a monosomy. The abnormalities affecting the X chromosome may occur in only a percentage of cells in the body; this is called mosaicism. Generally, the more cells that contain the abnormal or missing chromosome, the worse a disorder will be. The loss of all or part of the X chromosome that causes Turner syndrome occurs after the egg has been fertilized and appears to be a random event. There is nothing the parents did to cause the disorder. Turner syndrome is one of the most common chromosomal disorders. In rare instances, Turner syndrome is caused because genetic material on the X chromosome is duplicated or the chromosome forms a ring or also has genetic material from the Y chromosome.
Support groups offer extensive information about Turner syndrome. The Turner Syndrome Society of the United States offer a detailed guide called Turner Syndrome: A Guide for Families.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/turner-syndrome/overview/42753 • DATE UPDATED: 2017-11-14
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Backeljauw P. Clinical manifestations and diagnosis of Turner syndrome. UpToDate Inc. website. http://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-turner-syndrome
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